This project provides statistical, operational and coordinating support for the design, conduct, and analyses of, as well as reporting on, clinical trials in the therapy of malignant diseases conducted by the Cancer and Leukemia Group B. It services the cooperative research of 600 scientists in over 75 international hospitals and clinical centers. About 10 new investigations are undertaken each year, while an average of 30 studies are accruing 2000 patients with a variety of cancers and leukemias each year. These studies range in character from the investigation of potential therapeutic effects on new chemotherapeutic agents in advanced cancer patients to the systemic search for curative combinations of surgery, radiotherapy, chemotherapy and immunotherapy in newly diagnosed cancer patients, as well as formal investigation of the psychosocial aspects of cancer and its treatment. Uniform data are provided by these experiments, centrally collected, processed, analyzed and stored, and interim results are regularly reported to participating physicians. These data now form a library of over 20,000 cancer patients treated in accordance with carefully designed experimental therapeutic trials over two decades of Group research.